diff --git a/drf_spectacular/plumbing.py b/drf_spectacular/plumbing.py
index e03b866b..e3c1b1cc 100644
--- a/drf_spectacular/plumbing.py
+++ b/drf_spectacular/plumbing.py
@@ -526,8 +526,8 @@ def safe_ref(schema: _SchemaType) -> _SchemaType:
 
 def append_meta(schema: _SchemaType, meta: _SchemaType) -> _SchemaType:
     if spectacular_settings.OAS_VERSION.startswith('3.1'):
-        schema = copy.deepcopy(schema)
-        meta = copy.deepcopy(meta)
+        schema = schema.copy()
+        meta = meta.copy()
 
         schema_nullable = meta.pop('nullable', None)
         meta_nullable = schema.pop('nullable', None)
diff --git a/tests/test_extend_schema.py b/tests/test_extend_schema.py
index 3dfedcf5..9a561b9d 100644
--- a/tests/test_extend_schema.py
+++ b/tests/test_extend_schema.py
@@ -248,10 +248,13 @@ class XSerializer(serializers.Serializer):
     def view_func(request, format=None):
         pass  # pragma: no cover
 
-    assert_schema(
-        generate_schema('x', view_function=view_func),
-        'tests/test_extend_schema_field_with_dict_oas_3_1.yml'
-    )
+    schema = generate_schema('x', view_function=view_func)
+
+    assert schema['components']['schemas']['X']['properties'] == {
+        'field1': {'readOnly': True, 'type': ['string', 'null']},
+        'field2': {'readOnly': True, 'type': ['string', 'null']},
+        'field3': {'readOnly': True, 'type': ['string', 'null']}
+    }
 
 
 def test_layered_extend_schema_on_view_and_method_with_meta(no_warnings):
diff --git a/tests/test_extend_schema_field_with_dict_oas_3_1.yml b/tests/test_extend_schema_field_with_dict_oas_3_1.yml
deleted file mode 100644
index ae8d8395..00000000
--- a/tests/test_extend_schema_field_with_dict_oas_3_1.yml
+++ /dev/null
@@ -1,64 +0,0 @@
-openapi: 3.1.0
-info:
-  title: ''
-  version: 0.0.0
-paths:
-  /x:
-    post:
-      operationId: x_create
-      tags:
-      - x
-      requestBody:
-        content:
-          application/json:
-            schema:
-              $ref: '#/components/schemas/X'
-          application/x-www-form-urlencoded:
-            schema:
-              $ref: '#/components/schemas/X'
-          multipart/form-data:
-            schema:
-              $ref: '#/components/schemas/X'
-      security:
-      - cookieAuth: []
-      - basicAuth: []
-      - {}
-      responses:
-        '200':
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/X'
-          description: ''
-components:
-  schemas:
-    X:
-      type: object
-      properties:
-        field1:
-          type:
-          - string
-          - 'null'
-          readOnly: true
-        field2:
-          type:
-          - string
-          - 'null'
-          readOnly: true
-        field3:
-          type:
-          - string
-          - 'null'
-          readOnly: true
-      required:
-      - field1
-      - field2
-      - field3
-  securitySchemes:
-    basicAuth:
-      type: http
-      scheme: basic
-    cookieAuth:
-      type: apiKey
-      in: cookie
-      name: sessionid